The overall objective of this proposal is to contribute to a greater understanding of the cellular elements involved in the prevention and in the pathogenesis of periodontal disease by continuing to investigate the participation of cell mediated immune phenomena occurring in the tissues affected by periodontal inflammation. Numerous experiments suggest that the understanding of the interplay between immune cells and the cells of the periodontium is essential to progress in this investigative area. Specifically, this proposal seeks support to delineate the role that suppressor factor(s) from thymus derived theta positive cells play on mouse gingiva. Established techniques of immune reconstitution along with histological procedures will be employed to determine whether the administration of suppressor factors to dinitrofluorobenzene immunized mice will alter the course of periodontal tissue breakdown.